diff --git a/syndicate/patterns.py b/syndicate/patterns.py
index 91807f9..002431e 100644
--- a/syndicate/patterns.py
+++ b/syndicate/patterns.py
@@ -4,10 +4,10 @@ from preserves import preserve
 
 _dict = dict  ## we're about to shadow the builtin
 
-_ = P.Pattern.DDiscard(P.DDiscard())
+_ = P.Pattern.discard()
 
 def bind(p):
-    return P.Pattern.DBind(P.DBind(p))
+    return P.Pattern.bind(p)
 
 CAPTURE = bind(_)
 
@@ -48,7 +48,7 @@ def quote(p):
     elif isinstance(p, Record):
         return _rec(p.key, *map(quote, p.fields))
     else:
-        return P.Pattern.DLit(P.DLit(P.AnyAtom.decode(p)))
+        return P.Pattern.lit(P.AnyAtom.decode(p))
 
 def lit(v):
     if isinstance(v, list) or isinstance(v, tuple):
@@ -60,21 +60,41 @@ def lit(v):
     elif isinstance(v, Record):
         return _rec(v.key, *map(lit, v.fields))
     else:
-        return P.Pattern.DLit(P.DLit(P.AnyAtom.decode(v)))
+        return P.Pattern.lit(P.AnyAtom.decode(v))
+
+def seq_entries(seq):
+    entries = {}
+    for i, p in enumerate(seq):
+        if p.VARIANT != P.Pattern.discard.VARIANT:
+            entries[i] = p
+    np = len(seq)
+    if np > 0 and (np - 1) not in entries:
+        entries[np - 1] = P.Pattern.discard()
+    return entries
+
+def unlit_seq(entries):
+    seq = []
+    if len(entries) > 0:
+        try:
+            max_k = max(entries.keys())
+        except TypeError:
+            raise Exception('Pattern entries do not represent a gap-free sequence')
+        for i in range(max_k + 1):
+            seq.append(unlit(entries[i]))
+    return seq
 
 def unlit(p):
     if not hasattr(p, 'VARIANT'):
         p = P.Pattern.decode(p)
-    if p.VARIANT == P.Pattern.DLit.VARIANT:
-        return p.value.value.value
-    if p.VARIANT != P.Pattern.DCompound.VARIANT:
+    if p.VARIANT == P.Pattern.lit.VARIANT:
+        return p.value.value
+    if p.VARIANT != P.Pattern.group.VARIANT:
         raise Exception('Pattern does not represent a literal value')
-    p = p.value
-    if p.VARIANT == P.DCompound.rec.VARIANT:
-        return Record(p.label, map(unlit, p.fields))
-    if p.VARIANT == P.DCompound.arr.VARIANT:
-        return list(map(unlit, p.items))
-    if p.VARIANT == P.DCompound.dict.VARIANT:
+    if p.type.VARIANT == P.GroupType.rec.VARIANT:
+        return Record(p.type.label, unlit_seq(p.entries))
+    if p.type.VARIANT == P.GroupType.arr.VARIANT:
+        return list(unlit_seq(p.entries))
+    if p.type.VARIANT == P.GroupType.dict.VARIANT:
         return _dict(map(lambda kv: (kv[0], unlit(kv[1])), p.entries.items()))
     raise Exception('unreachable')
 
@@ -82,10 +102,10 @@ def rec(labelstr, *members):
     return _rec(Symbol(labelstr), *members)
 
 def _rec(label, *members):
-    return P.Pattern.DCompound(P.DCompound.rec(label, members))
+    return P.Pattern.group(P.GroupType.rec(label), seq_entries(members))
 
 def arr(*members):
-    return P.Pattern.DCompound(P.DCompound.arr(members))
+    return P.Pattern.group(P.GroupType.arr(), seq_entries(members))
 
 def dict(*kvs):
-    return P.Pattern.DCompound(P.DCompound.dict(_dict(kvs)))
+    return P.Pattern.group(P.GroupType.dict(), _dict(kvs))